The majority of the grass forage pastures in the United States are located in regions that are subjected to extreme climatic conditions with hot, dry summers and very cold winters with no snow cover. The predominant cool season perennial grass grown in the Southeast United States and transition zone is tall fescue (Festuca arundinacea).
Summer survival of tall fescue is related to presence of living fungal endophyte (Neotyphodium coenophialum) in the plants. For example, the presence of endophyte in tall fescue as well as perennial ryegrass can enhance drought tolerance, summer survival, insect tolerance and disease tolerance. However, cattle grazing forage from most endophyte-infected tall fescue cultivars suffer from fescue toxicosis. Fescue toxicosis results from ingesting ergot alkaloids. Ergovaline is considered to be the main ergot alkaloid responsible for most animal problems.
Therefore, new endophytes and forage grasses containing endophytes are needed, such as those that have a less toxic effect on grazing animals.